The spine (vertebral column) consists of thirty-three superimposed bones termed vertebrae. Of these the upper twenty-four remain separate throughout life and form three groups. The first seven are called cervical, the succeeding twelve thoracic (dorsal), and the last five lumbar. In adult life the last nine vertebras ankylose to form two composite bones named the sacrum and the coccyx. The sacrum is formed by the fusion of five vertebrae from the twenty-fifth to the twenty-ninth inclusive; the four terminal are vestigial, and form the coccyx. In order to gain a general notion of the characters of a vertebra, it is desirable to select a bone from the middle of the thoracic series.
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The skull, when viewed from above, presents an oval outline; the posterior part is broader than the anterior. The bones seen in this view are the frontal, parietals and the interparietal portion of the occipital. In a skull of average width the zygomata come into view, but in very broad skulls they are obscured.
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The osseous structure is peculiarly fitted, by its solidity and hardness, not only to give support to the soft parts, but also to furnish points of attachment to the muscles, by which the different movements are executed. This solid framework of the body is made up of a number of separate pieces, the aggregate of which has been termed " the skeleton" (sceletum, σχελλω, to dry.)
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The occipital bone, (lat.: os occipitis, french: Os occipital) is situated at the posterior part of the base of the skull; broad behind, much narrowed before, of a trapezoid figure, presenting two surfaces, four borders, and four angles. To place the bone in its natural position, hold it so that the great foramen and the articulating processes beside it shall look directly downwards; the thick process in front of the foramen will then project forwards into the base of the Skull, Whilst the broad expanded part behind it arches upwards and a little forwards, forming the posterior wall of the Cavity.
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This is the u-shaped bone, so named from some resemblance to the Greek letter v. It is occasionally called the lingual bone, from its important relations with the tongue; it is situated at the base of the tongue, and may be felt between the chin and the thyroid cartilage. It consists of a body, two cornua, and two cornicula.
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Osteology is the study of the bones which form the various parts of the skeleton.
The skeleton includes/understands, a cartilagineuse part and an osseous part.
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The frontal bone, (os frontis, coroaale,) situated at the anterior part of the skull, and upper part of the face, is divisible into two parts (frontal and orbital), differing in size and position: of these, one extends upwards towards the vertex, forming three-fourths of the extent of the bone; the other, inferior and horizontal in its direction, forms the roof of the orbits. To place the bone in its natural position, hold it so that the orbital plates shall look downwards, and the smooth convex surface forwards.
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